I'm trying to extract images from Atari ST STeem memory dumps (and I hope I can ask here, without having my head ripped off - I'm doing this out of interest because I want to compare Amiga and Atari graphics)

I found a thread in an Atari ST forum, where you inquired about ripping Atari ST images. There you stated that Maptapper would be able to read STS files.

My version (0.8.4 Build 57) doesn't offer support for STS files. It's not stated in the SaveState requester and it doesn't offer to parse the color palette.

I'm also having difficulties putting the Atari images together again - despite Maptapper's Atari ST mode.

The latest version I've been working on is build 61 and it can parse STS files. There's a few quirks that need cleaning up before it's ready to release but I can give you a beta version if you wish. Send me an email!

The main problem is that the Gfx tab has so much stuff to deal with various new options I needed that it takes up more than 768 pixels of height so it's a bit of a mess at present. But it has a lot of extra features, able to construct maps that are drawn upwards and right to left etc. It can also perform calculations on each tile in a map such as dividing the number by 160 and subtracting 1 etc etc...